A device of this type is already known from EP 0 687 749 B1. This document describes an MOCVD reactor comprising a rotationally symmetrical process chamber, the floor of which forms a substrate holder. The ceiling of the process chamber, opposite the floor, has a multiplicity of narrow, closely adjacent outlet openings, the outlet openings being connected there in an alternating manner to two different rear chambers. Gases that are different from each other are introduced into these chambers and then flow into the process chamber through the outlet openings.
MOCVD reactors comprising a gas inlet member similar to a shower head are additionally also already known from DE 10136858 A1 and DE 10217806 A1.
U.S. Pat. No. 6,500,266 B1 describes a reactor in which a separate cover is provided for the temperature calibration.
With the aforementioned devices, it is possible to deposit crystalline layers, in particular of a III-V material, on substrates disposed on the substrate holder. In order to measure the temperature profile on the substrate holder, which is heated from the rear, it is known to measure its temperature pyrometrically, for example by means of photodiodes. For this purpose, these photodiodes may be disposed vertically above the floor within the gas inlet member. These sensors are then removed again for the operating process, that is the depositing of layers.
It is also known to measure the temperature of the surface of the substrate holder or of the substrates during the growing process.
It is an object of the invention to develop a device of the generic type with a view to better observation of the surface temperature of the substrate holder.